Foldable mattress



FIG. 1 is a front-left perspective view of a foldable mattress shown in fully folded configuration, showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a front-left perspective view thereof, shown in fully unfolded configuration. 

The ornamental design for a foldable mattress, as shown. 